Abstract Tungsten (0)-and rhenium (I)-catalyzed reactions of acetylenic dienol silyl ethers based on the concept of geminal carbo-functionalization of alkynes are reported. Treatment of 3-siloxy-1, 3-diene-7-ynes with catalytic amounts of [W (CO) 6] or [ReCl (CO) 5] under photoirradiation conditions gives synthetically useful bicyclo [3.3. 0] octane derivatives in good yields. Extremely high catalytic activity is noted for the rhenium (I) complex. The ...